Spring jack



March 23 1926. 1,577,568

L. c. DENSLOW SPRING JACK Filed March 1, 1924 gnuemloz L a. Deruslow.

sets.

Patented Mar. 235, i926.

unirrn st e ATENT PRING JA K- Applioation filed March 1,

To all whom "it may concern:

Be it known that I, LORENZO C. DnNsLow, acitiZen of the United States, residing at Falls Church, in the countyv of Arlington and State of Virginia, have invented cer tain new and useful Improvements in Spring Jacks, of which the following is a specification.

This invention relates to an improved spring jack and while being well adapted for general application ismore particularly designed for use in radio work.

The invention seeks, among objects, to provide a jack which will effect an economy in the depth of space occupied by the jack, soas to permit more compact assembling of radio sets.

The invention seeks, as a further object, to provide a jack involving a novel arrangement of the spring contacts employed so that said contacts will be readily accessible forthe connection of circuit wires thereto, while the possibility of current leakage or short circuitingbetween the contacts will be effectually avoided.

And the invention seeks, as a stillfurther object, to provide a jack which will be of extremely simple construction to the end that the device may be manufactured and sold at moderate cost.

Other and incidental objects will appear hereinafter.

In the drawings:

Figure l is a perspective view showing a single circuit jack embodying the present invention,

Figure 2 is a longitudinal sectional view through the jack, and showing a conventional plug inserted therein,

Figure 3 is a perspective view showing a double circuit jack constructed in accordance with the invention, and

Figure 4 is a sectional view showing a further modification of the invention.

In so far as I am aware, spring jacks heretofore used in radio work have all beenof the type commonly employed in the telephonic art, the usual jack of a typical telephone switch boardsimply being borrowed, so to speak, and pressed into service in building radio sending and receiving lVhile being entirely efficient for its intended purpose, the usual telephone jack is, however, subject to many disadvantages in'the *new environment of a radio set. (living to the proximity of other parts, difbecomes handling ofthe jack, with the result that 1924-. Serial no. 696,231.

ficulty is often experienced in reaching the connector lugs of the spring contacts for the attachment of wires thereto. Furthermore, these lugs are very close together, rendering it extremely diiiicult for the amateur to properly secure the wires. Also, the insulation between the contacts often impaired, under. inexperienced the set of the amateur, when finished, contains a hidden fault in the jack and, in this connection, it may also be noted that, when soldering paste is allowedto flow, during a soldering operation, onto the insulation of the usual telephone jack, the paste tends to collect about the insulation with the ,resuit that current leakage often ensues while the finished set is rendered noisy by the corrosive action of the paste. Another dis advantage of the usual telephone jack lies in the fact that such a jack, when mounted on the panel of a radio set, projects a con siderable distance at the back of the panel and thus occupies an unwarranted depth,

necessitating the spacing of other instruments of the set rearwardlyfromthe panel or resorting. to the expedient of a shelf. The present invention, therefore, seeks to provide a "jack which will overcome the various disadvantages noted and which will be especially adapted to the peculiarities of radio installation.

Referring now more particularly to Fig ures 1 and"2 of the drawings,l have illustrated a single circuit jack embodying the present invention. Abase 10 of suitable insulating material is employed and formed through the base is a medial plug opening 11. The base is flat, so that, as suggested in Figure .2, the base may be rested against a panel, as conventionally illustrated at 12,v

and formed through the base are appropriately located openings 13 to receive screws or other suitable fastening devicesld securing the base to the panel, the panel being provided, of course, with an opening to register with the opening 11 of thecase.

Inserted through the base near the ends thereof are binding posts 14 alining with the plug opening 11 and mounted upon the binding posts are spring contacts indicated for convenience at 15 and 16. These contacts are provided with slots 17 to'freely receive the posts 14L so that said contacts may be readily adjusted with respect to the opening 11 and securing the contacts in ad justed position are nuts 17 screwed upon the posts. Preferably, the posts also carry thumb nuts 18 so that circuit wires may be readily secured to the posts.

The spring contacts 15 and 10 extend toward the plug opening 11 in radial relation to the axis thereof and are bent near theirouter ends to diverge or incline away from the base while at points medially thereof said contacts are again bent so that the free end portions 01 the contacts lie in approximately parallel relation. In other words, the contacts are oli'set so that the contacts stand away from the base throughout the major portion of their length while the free end portions of the contacts approach parallelism and, as will now be observed, the contact 16 is offset at a greater angle than the contact 15 so that the free end of the former contact overhangs the free. end of the latter contact in spaced relation. vAt their tree ends, the contacts are turned laterally away from the base to term rounded contact lips 19 and 20 and, as will now be observed, the contact 15 is of such length that the lip 19 thereof does not quite touch the axis of the plug opening 11 while the contact 16 is longer than the contact 15 so that the tree end of the contact 16 extends across said openin As will now be seen in view of the foregoing when a plug, as conventionally illus trated at 21, is inserted through the panel 12 and through the plug opening ll of the base 10, the tip of the plug will lirst strike the lip 19 of the contact 15 for deflecting the free end of said contact, when the contact will be flexed away from the base and thus brought under tension to bear against the side of the plug shank. As the plug is then advanced, the tip of the plug will next strike the lip 20 of the contact 16 when, in like manner, the free end of the contact 16 will be deflected and said contact llexed away from the base and accordingly brought under tension against the side of the tip. is will be noted, the contact 16 is of such length that when the plug has reached the limit of its inward movement, the lip 20 of said contact will seat in the groove at tile base of the tip so that the plug will thus be yieldably gripped between the contacts while the lip 20 of the contact 16 will cooperate with the tip for holding the plug against accidental retraction. In this connection it is to be observed that due to the acuteness of the angles between the base and the free ends oi the contacts, initial retractive movement of the plug will slightly drag said ends of the contacts toward the base and tend to wedge the plug between the contacts so that the plug will thus be locked against accidental endwise displacement. Eflicient and proper electrical connection between the contacts and the plug will thus be maintained. By

adjusting the contacts upon the posts 14:, the contacts may be positioned to properly cooperate with plugs of different length and likewise, compensation may be readily made for variation in the thickness of different panels. When the plug is inserted or removed, the plug will, of course, shift across the lips 19 and 20 of the contacts, so that the incident wear on said lips will maintain the lips bright and clean. Furthermore, the binding posts 14- are, comparatively speaking, widely separated, so that circuit wires may be readily connected to said posts and since the contacts are arranged in radial relation to the plug opening of the base instead of parallel to the axis of said opening, as in the usual j ZlCli, the device is rendered con'ipact and will occupy but very little depth at the back of the panel.

In Figure 3 of the drawings, I have illustrated a slight modification of the invention embodying a double circuit jack. In this modification, I employ a base 22 of suitable insulating material and formed in the base is a plug opening 23 in juxtaposition to which are arranged spring contacts 52 i and 25, as in the prior en'ibodiment, said contacts being mounted on binding posts 26. Resting fiat against the base to extend transversely beneath the tree ends of the contacts 24 and 25 are cooperating contacts 27 and 28 secured near corresponding ends thereof by binding posts 29 similar to the binding posts 26 and near their opposite corresponding ends by screws 30. At the latter ends there of, these contacts are termed with upstanding contact lugs 31 and 32 normally seating the contacts at and 25, the lug 32 being somewhat longer than the lug 31. Thus, under ordinary circumstances, a circuit will be closed through the contacts 2% and 27 and through the contacts 25 and 28. However, when the plug is inserted through the plug opening 23 to engage the free ends of the contacts 2d and 25, these contacts will be lifted away from the contact lugs 31 and while the contacts ill and 25 will cooperate with the plug to coinpelte a circuit therethrough. This modified structure thus also provides a very efficient device and, as will be seen, the advantages incident to the preferred form of the invention are also resident in the modified structure.

In Figure 4 of the drawings, I have illustrated a further modified structure wherein I employ a base 33 having a plug opening 8% and mounted upon the base to extend toward said opening, as in the preferred form of the invention, is a spring contact 35 adjustably secured by a binding post 36. Extending beneath the free end portion of he contact is a second contact 37 adjustably mounted by a binding post 38 and provided at its free end with an upturned lug 39 to cooperate with the contact 35. Ar-

nary circumstances, the contact 35 will seat against the lug 39 of the contact 3'? for closing a circuit through said contacts- However, when a plug is inserted through the opening 34, the contact 35 will be lifted out oi engagen'ient with the lug 39 of the contact 37 and shifted into engagement with the lug 42 of the contact 0 for closing a circuit through the contacts 35 and L0 while, at the same time, the contact 35 will, of course, make connection with the plug.

Having thus described the invention, what I claim is: v I

1. A spring jack including a base provided with an opening, spring contacts mounted upon the base at one side thereof and inclining away from said side of the base to impinge at their free ends against a plug inserted through said opening, and means connecting the contacts with the base for adjustment to vary the effective length of said contacts.

2. A spring jack including a base provided with an opening, spring contacts n'iounted upon the base at one side thereof and inclining away from said side of the base to impinge at their free ends against a plug inserted through said opening, said contacts being provided withslots, and means extending tl'irough said slots connecting the contacts with the base, the contacts being adjustable upon said means for varying the etiective length of said contacts.

3. As a new article of manufacture, a spring jack including, in combination, a separate .individual base provided with an opening, and spring contacts mounted upon and inclining away from the base each at an angle less than forty-live degrees, said contacts being bent medially to define angularly disposed free ends extending in substantially parallel relation to impinge at their free terminals against a plug inserted through said opening whereby initial retractive movement of the plug will slightly drag the free ends of the contacts toward the base and tend to wedge the plug therebetween for locking said plug against accidental displacement.

4. A spring jack including a base pr0- vided with an opening, and spring contacts mounted upon and inclining away from the base, one of said contacts extending at a less angle to the base than the other but each extending at an angle less than fortytive degrees and both of said contacts being bent medially to define angularly disposed free ends extending in substantially parallel relation to impinge at their free terminals againsta plug insert-ed through said opening whereby initial retractive movement of the plug will slightly drag the free ends of the contacts toward the base and tend to wedge the plug therebetween for locking said plug against accidental displacement.

5. A spring jack including a base having an opening, a contact carried by the base, and another contact inclining away from the base over the former contact to normally engage therewith and having its free end disposed to impinge a side of a plug inserted through said opening, the latter contact being movable by the plug away from the base out of engagement with the former contact.

6. A spring jack including a base having an opening, contacts carried by the base, and other contacts inclining away from the base at unequal angles over said first mentioned contacts to normally engage therewith and having their free ends staggered and disposed to impinge the sides of a plug inserted through said opening, the latter contacts being movable by the plug away from the base out of engagement with said first mentioned contacts.

In testimony whereof I aflix my signature.

LORENZO C. DENSLUW. -1 

